The Competition of Tidal Mixing and Freshwater Forcing in Shaping the Outflow from Hudson Strait

• Main Authors: Straneo, Fiammetta, Rainville, Luc
• Other Authors: WOODS HOLE OCEANOGRAPHIC INSTITUTION MA DEPT OF PHYSICAL OCEANOGRAPHY
• Format: Text
• Language: English
• Published: 2009
• Subjects: Physical and Dynamic Oceanography; Hydrology; Limnology and Potamology; *FRESH WATER; *TIDES; *STRAITS; *MIXING; *COASTAL REGIONS; PHYSICAL PROPERTIES; WATER; BIOCHEMISTRY; MELTS; BOUNDARY LAYER; MOISTURE CONTENT; VARIABLES; PRECIPITATION; PROFILES; VERTICAL ORIENTATION; TRANSPORT; PLUMES; RIVERS; STRATIFICATION; NORTH ATLANTIC OCEAN; BOTTOM; INTERNAL WAVES; BUOYANCY; GLACIERS; MOORING; ESTUARIES; OPTICAL PROPERTIES; MEASUREMENT; SPATIAL DISTRIBUTION; PROPAGATION; VELOCITY; MATHEMATICAL MODELS; HUDSON BAY(CANADA); Canada; Hudson; Hudson Bay; Hudson Strait; glacier*; North Atlantic; Sea ice
• Online Access: http://www.dtic.mil/docs/citations/ADA527262; http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA527262

River discharge, precipitation and, in the high-latitudes, melt water from sea-ice or glaciers give rise to fresh and buoyant plumes which flow along topographic margins. These plumes form in coastal environments and are subject to a variety of processes, including tidal mixing and surface forcing, which rapidly modify their properties and their structure. We investigate how tidal mixing, surface forcing and a variable fresh water source act to modify a fresh, buoyant plume using a combination of observations, theory and numerical models. The objectives are: Investigate the spatial characteristics of the plume from the moored data including its vertical structure, fresh water content, the bottom boundary layer, and the freely propagating internal tides; investigate the tidal to interannual variability in the flow and better understand its relation to the tidal forcing as well as the local and remote wind-forcing and buoyancy forcing; and expand the theory for a buoyant gravity plume over sloping topography to include strong mixing. A new and unique set of measurements from Hudson Strait, one of the most tidally energetic straits in the world and an important channel for freshwater transport into the North Atlantic is available to us to address our objectives (Figure 1). The 3-year moored data set, which includes high resolution property and velocity profiles, as well as optical backscatter and fluorometer data, is ideal to look at the interplay of the variable stratification, driven by input of freshwater, and the mixing driven by the tides, two competing mechanisms controlling the physical and biochemical properties of many estuaries and straits. Our analysis focuses on the barotropic and baroclinic tides, the bottom boundary layer, and the buoyant current and on their spatial and temporal variability.